Grub control and organic lawn care appear to me to be incompatible; but there is much about either that I do not know. Grubs of different insects have very different life cycles. There are times when grubs are deep enough underground as to be beyond the reach of control agents. ID and life cycle of the grub you have is the first step.

You can buy beneficial nematodes to take care of the grubs. The nematodes carry a disease that is fatal to larvae in about 24-48 hours. I get them from the link below.

Here is a link that might be useful: Beneficial Nematodes

Since nematodes and Milky Spore are expensive and you mentioned it was out of your range for a large lawn, I'd go with the grub killer. No, it's not organic. It's not an optimal solution. You know that already.

I don't know how specific Merit is, but if it's a general insecticide you do run the risk of wiping out your micro-arthropods that happily do a good job keeping your lawn disease and fungus free. (Sometime, lookup the lowly fungus gnat...they're one of the most amazing and unconsidered creatures in our grass and gardens!)

But if you gotta, you gotta. It's kind of early for the grubs to be back in Zone 5b (I'm a 5c/6a crossover). And when they do, they're third instar and about to become adults. There's no reason to try killing them now because it won't work very well.

I'm not sure what the bag recommends, but the one time I was forced into using (gag) GrubX I applied it about two weeks before I expected to see the adults. The next year, no grub damage (on my parents' lawn at the time).

Maybe you could start a small fund for next year for Milky Spore? It works fairly well in our colder climate--grubs counts on my current lawn and in the gardens were already dropping last fall and I expect far fewer still this year. Plus it lasts years until it micro-evolves to a less-killing genome. Then you just reapply.

Thank you for your help! I knew I could count on you guys! :)

Natureperson, why did you come to an organic forum to ask advice about chemical poisons? There are several other forums for that. If you don't want to be organic, go ahead and use your poisons, but please don't sucker us into the discussion on this forum.

I figured (s)he was hoping for a more organic answer...and in this case, given the stated cost limitation, regrettably I don't know of one.

http://nysipm.cornell.edu/publications/grubs/default.asp?metatags_Action=Find('PID','4')

I recently did some grub research since I found some in my soil while I was digging a planting bed. I was relieved to find that they are present in almost all lawns and it's only in certain numbers that they can overtake a lawn's root system. I found the above link helpful. In a nutshell, there's no sense in treating grubs in spring since they are already adults and have done their damage. They have to be treated at the larve stage in fall.

One way to keep the grubs out is to capture the adult Japanese beetles before they lay eggs. Traps made from a 5-gallon bucket of water with a light bulb hanging right above it apparently work well. It helps more if you use a shop light with a shade over it so the reflection of the bulb in the water looks like the bulb itself. They fly directly into the water and do not pass go. I've heard of 15 pounds of kill per night when the hunting is good. Then compost the bugs - they are extremely green.

Traps made from a 5-gallon bucket of water with a light bulb hanging right above it apparently work well

Thank you, thank you, thank you! I'll try this as soon as I start seeing adults! The Bag-A-Bug traps work well, but seem to attract adults from the surrounding counties (and perhaps a few that caught a commercial flight in).

There is a claim that you attract more bugs to your lawn with the trap. I'm relatively sure this is just someone's hunch. If you have a porch light, they are coming to that light anyway.